1. Field of Invention
The present invention relates to an apparatus that can be used, as a computer mouse device and as an enabling device for turning ordinary pen-shaped objects into digital instruments, for the purposes of cursor control, inputting figures, symbols, characters and the like into a data processing device, such as a computer.
2. Prior Art
Conventionally, a keyboard, mouse, digitizer, light pen, and tablet, etc. have been used as an input apparatus employed in a computer apparatus or the like. There is a growing range of computing devices, from those that are small and portable to those that are bigger and remain on desktop. Ergonomic human interaction with computers is an important problem to be addressed, particularly with the growing variety of small devices.
There is a limitation on making a keyboard small-sized from the viewpoint of human interface, and the keyboard is not a practical input apparatus for a portable device. A conventional mouse device is made to be gripped by the hand and to be enclosed by the palm of the hand. The arrangement of sensing technology in a mouse device is typically proximal to the surface. Mouse usage is ubiquitous. Although mouse device can be made in a small-size and used as a pointing device, it is not suitable for inputting figures and characters, etc. into a data processor.
Since it is clumsy to use a keyboard along with a small portable device such as Personal Digital Assistant (PDA) or cellular phone, it is highly desirable to use a pen-shaped device with such small devices. For this reason, on many occasions, a pen-shaped input apparatus employing a tablet and pen have been adopted as the input apparatus for a portable device. The size of the tablet is small, especially in small portable devices, and this restriction does not allow providing pen-input with ease.
Use of tablet-based pen-input apparatus is not common in conventional desktop computer arrangement for several reasons. Even though larger tablets can be used on a desktop, such arrangements increase the price of the input accessories needed and also clutter the desktop.
To overcome the problem of tablet size, pen input apparatuses without relying on tablets have been developed. There are two kinds of such pen devices, based on their overall configuration. One type of devices is dedicated pen devices; they are dedicated in that they are manufactured in a specific pen size. The other type is pen “attachment” devices that can be attached to an external pen object; these devices can be made to accommodate different pen sizes.
Some of the dedicated pens allow ink flow for writing, whereas others do not. There are in general two classes of dedicated pen devices, based on the sensing technology employed. One class of sensing technologies places all the sensing mechanism contained within the pen (e.g. U.S. Pat. No. 6,229,102) whereas the other class involves external references where at least part of the sensing mechanism is placed remotely from the pen (e.g. U.S. Pat. No. 6,703,570).
Early attempts at dedicated pen devices, with self-contained sensing mechanism, relied on mechanical roller ball based arrangements wherein at least one ball at the tip of the pen is in contact with the writing surface (e.g. U.S. Pat. No. 5,291,213) and the rotation of the ball is electromechanically sensed to calculate relative motion. Optical means of detecting relative motion, based on patterns on the ball, are also known in digital pens (e.g. U.S. Pat. No. 6,498,604). Other attempts have used inertial sensors to calculate motion of tip of pen. Dedicated devices are typically offered in larger sizes that may not be comfortable to grip. When the dedicated pen devices involve ink flow, they can be cumbersome to maintain due to the need for customized ink reservoirs. These factors do not make such pen devices suitable for wide usage.
As stated earlier, dedicated pen devices that rely on external references are known. Many of those devices have used ultrasound and radio frequency technologies (e.g. U.S. Pat. No. 6,577,299). Some have employed optical technology which relies on special markings on writing surface that provide absolute coordinate information. These technologies are expensive in general and are appropriate for use in specific applications such as the use of digital pen in filling forms, in an office setting.
All these developments in dedicated digital pens have left a void in that these devices are neither practical to manufacture in a variety of suitable sizes and weights at a low cost, so that they can be used by a variety of users, nor do they enable the use of commonly used pen-shaped objects to provide digital input.
There are a couple of attachment type pen devices known in prior art. One of them, disclosed in U.S. 2004/179000, allows a pen to be inserted into the attachment, but it is bulky in nature. The other device, disclosed in U.S. Pat. No. 6,906,703, uses an attachment rigidly fixed to a pen and contains accelerometers to detect motion. Rigid attachment of accelerometers to a pen reduces the accuracy of detected motion due to the effects of gravity component on accelerometer signals. Further, in said U.S. Pat. No. 6,906,703, there is no means to distinguish between motion of pen on the surface and the motion of pen when it is not in contact with the surface.
In general, electronic hardware used in pen devices is more complicated than that used in mouse devices. This is because there are several components of motion that need to be accounted to accurately track pen movement. These motion components are: (i) motion of pen-tip on the surface, (ii) motion of pen tip away from the surface, but on a plane parallel to the surface, (ii) static inclination angle of pen with respect to the normal direction of the surface and (iii) dynamic inclination changes of the pen with respect to the normal direction of the surface.
In other words, among different users and based on user's style of gripping the pen, there can be variations in (i) the inclination of pen with respect to surface at the beginning of pen use and subsequent changes during pen use, and (ii) the amount by which the pen is lifted off the surface. These factors impact the accuracy of relative motion sensing means in pen devices.
It can be appreciated that although there are some similarities between sensor technologies used in mouse devices and pen devices, the complicated nature of pen motion necessitates additional sensors for accurate tracking of pen motion. In general, this makes the digital pen devices bulkier and more expensive.
For small portable devices, the need to have a low cost digital pen that is independent of tablet is crucial. In providing pen input to small devices such as PDA or cellular phone, it is much easier to write on a nearby surface than on a small tablet on the device. This will allow ergonomic pen interaction. But such devices are not commercially realized.
For large computing devices, such as desktop computers, it is important to allow pen input albeit at lower cost and without cluttering the desktop. For desktop computers, in some cases, it is preferable to be able to switch between the mouse-input and pen-input with ease.
In prior art, pen devices are known to be used for real-time (pen-input) or for offline (pen-computer) input purposes. A device that can be used both as a pen-input device and pen-computer device is not commonly available.
Not surprisingly, compared with digital pen devices, the computer mouse devices have achieved remarkable success while being available at a low cost. Particularly, the accuracy of computer mouse has increased with the introduction of optical sensing technology. In conventional mouse devices, the motion sensing means and related electronics are lightweight in nature; it is usually the shell of the mouse device that is made heavier to provide appropriate feel for the user.
Although the accuracy and ease of use of the mouse devices have vastly improved, the function performed by the mouse device has been restricted to cursor control, for several decades. Several mouse configurations are known for employing the mouse device for uses other than cursor control, but these modifications are not commercially available.
It is clear that there is a need for using both the mouse shaped device and low-cost ergonomic pen-shaped device (independent of tablet) in routine computer interaction. One possibility for having both mouse and pen function is to have a mouse device and a pen device separately connected to a host device, functioning independent of each other.
A port for a mouse device is commonly available in computers whereas an additional pen device would require use of another port. Also, the number of digital devices that need to be connected to a host device has increased in recent years. On the one hand it is difficult to have a dedicated port available for each device and on the other hand it becomes a chore to plug peripheral devices in and out, in order to share ports. So it is preferable to make devices that perform more than one function while sharing the connection to the host device. This will also lead to reduction in the cost of input accessories.
Combining mouse device functions and pen device functions in one apparatus have been attempted. One such attempt is a pen-shaped device, sold by a company Finger Systems of Korea, that can be used to mimic mouse-like functionality. One limitation with such device is that it is difficult to provide mouse-input using a pen-shaped device. Another attempt in prior art, disclosed in WO2005010741, has a pen that has a back end shaped like a mouse. This makes the pen heavier at the top and bulkier to handle.